Size for an AG boil kettle?

Heya folks, I just made the jump and constructed a 10-gallon mash tun to get ready to start making all-grain brews.

However, I looked up, and realized I only had a 5-gallon boil kettle! It worked all right for extract brewing, but will it be enough for all-grain? I've heard that there's more liquid in an all-grain brew, is that correct?

What size kettle is needed for all-grain brewing? And if I need to buy a new one, what should I do with the old one? I'm leaning towards converting it into a crab steamer, 'cause there ain't nothin' better than crab legs to go with beer!

Thanks for your input. I'm excited to go all-grain!

For a 5-gallon AG batch, most people start with a 5.5 gal recipe to make sure the full 5 gal makes it to the fermenter after racking losses, samples, etc.

Given a 5.5 gal batch size, you'll start boiling with somewhere between 6.5 and 8+ gallons of wort depending on the beer style, your system efficiency, desired boil length, evap rate, etc.

You can squeeze by with a 7.5 gal turkey fryer (many people here do).

You'll have fewere headaches and more flexibility if you go to 9-10 gallons.
If you think you'll ever want to do 10-gallon batches, might as well go immediately to a 15+ gallon pot, or a keggle. Otherwise you'll be having this discussion again

Use the old pot as a hot liquor tank (HLT)